Primary structure of bovine alpha 2-antiplasmin

The primary structure of bovine alpha 2-antiplasmin (alpha 2AP) has been determined from cDNA and partial peptide sequencing. Mature bovine alpha 2AP contains 470 residues and is 6 residues longer than human alpha 2AP. Alignment of the two protein sequences show that 81% of their amino acid residues are identically located. Bovine alpha 2AP has 5 N-linked carbohydrate groups, of which four are found in human alpha 2AP (Asn105, 274, 288 and 295). Asn227 is the fifth carbohydrate attachement site in bovine alpha 2AP. The 3 Cys residues of bovine alpha 2AP are present as an unpaired residue (Cys131) and as a pair in a disulfide bridge (Cys49-Cys122). The assignment of the bridge in bovine alpha 2AP is at variance with the previous assignment of the two disulfide bridges in human alpha 2AP [Lijnen, H.R. et al. (1987) Eur. J. Biochem. 166, 565-574].